MasterMet colloidal silica

Identity and product relationships

MasterMet is Buehler’s 0.06 µm amorphous colloidal silica suspension for final polishing. Its product prose gives about pH 10.5 and its ordering table gives about pH 10. These are approximate descriptions. The separate 0.02 µm MasterMet 2 (40-6380) carries Buehler’s non-crystallizing claim. MasterPrep contains alumina and MasterPolish blends alumina with colloidal silica. Buehler product descriptions and ordering table.

The US MasterMet SDS identifies a mixture and covers 40-6370-006, 40-6370-064, and 40-6370-128. Its recommended use is laboratory chemicals. US SDS, 23 May 2022, sections 1–3.

Abrasive size, dispersion, and formulation

The nominal designation does not specify surface roughness or maximum particle size. This is an interpretation of the size statement above. A derived unit conversion gives 60 nm because 1 µm equals 1,000 nm. This conversion adds no particle-distribution information.

The older UK-hosted SDS lists water and silica, each at 40–60% by weight. Those broad disclosure intervals do not specify an exact recipe. It reports no particle-size distribution data. These statements apply to that document's two listed package codes and revision. UK-hosted EGHS SDS, 10 February 2021, sections 1, 3, and 9.

The 2022 US SDS lists no ingredients requiring disclosure under its section 3.2 criteria, but names water and amorphous silica in section 8. That disclosure rule does not establish a complete formulation or an absence of additives. Neither reviewed MasterMet SDS establishes an ammonia concentration or an ammonia-free formulation. US SDS, sections 3 and 8.

Synthesis. A colloidal suspension describes dispersed abrasive particles. The historical SDS's water-miscibility entry, section 9, does not establish that all silica is molecularly dissolved. Product identity and nominal size remain separate from dispersion stability and lot-specific particle measurements.

Chemical-mechanical polishing and applicability

Buehler's May 2014 guide describes MasterMet as colloidal silica in a basic solution. It attributes polishing to chemical reaction with the specimen surface that helps the abrasive remove material. Its MasterMet entries cover steel and nickel- or cobalt-based alloys, nonferrous metals, and several other specimen categories. This is manufacturer application guidance, not a quantified comparison or a guarantee of deformation-free preparation. Quick reference guide, marked 05/14.

Buehler associates MasterMet with fine polishing of passive-film-forming materials, including aluminum alloys, refractory metals, silicon, and ceramics. Buehler application description.

Synthesis. These references support a role in metallographic preparation. They do not qualify every alloy, ceramic, coating, or multiphase specimen. A nominal abrasive size alone cannot establish removal rate, preserved edge geometry, or suitability for production deburring and finishing. Those outcomes depend on the specimen, cloth, equipment, and evaluated preparation method.

pH and source differences

Sources are the product page, 2014 guide, US SDS, and UK-hosted SDS.

Synthesis. These values describe an alkaline product but do not establish one exact release specification or a measured value for a supplied bottle. The sources do not explain whether the differences reflect rounding, document practice, or formulation history.

Packages, drying, and cleanup limits

The US table lists 40-6370-006 at 6 oz [0.18 L], 40-6370-064 at 64 oz [1.9 L], and 40-6370-128 at 128 oz [3.8 L]. These paired labels do not guarantee regional stock. Buehler recommends MasterMet 2 where extended air exposure raises crystallization concerns. No MasterMet drying time or restoration method is established. Buehler ordering and MasterMet 2 descriptions.

The US SDS classifies MasterMet as not classified under GHS US, while still specifying ventilation, protective gloves, safety glasses, and suitable clothing. Its spill guidance describes absorbent cleanup. These safety provisions do not establish a specimen-rinsing method or residue-free analytical surface. US SDS, sections 2, 6, and 8.

The older UK-hosted SDS classifies the mixture as not hazardous under CLP, yet section 11 states that skin irritation may occur. Different jurisdictional classifications and narrative cautions remain distinct. UK-hosted SDS, sections 2 and 11.

Source and coverage limits

Sources reviewed on 29 October 2026 PDT include the undated manufacturer product page, the complete one-page 05/14 guide, the seven-page US SDS revision 1.0 dated 23 May 2022, and the ten-page UK-hosted EGHS SDS revision 5 dated 10 February 2021. SDS revisions describe their named products and safety contexts, not polishing performance specifications. No complete additive formulation, current lot certificate, shelf-life claim, measured agglomeration behavior, or universal cleanup recipe was established.

Finishing process references covers the broader production-process distinction.